The Robert L.B. Tobin Land Bridge: A Wildlife Corridor Reconnecting a San Antonio Park

What it is

The Robert L.B. Tobin Land Bridge at Phil Hardberger Park is a vegetated overpass on San Antonio's north side allowing both wildlife and pedestrians to safely cross over the six lanes of Wurzbach Parkway below. It measures 189 feet long and 150 feet wide, built from arched steel girders and concrete and covered in soil deep enough to support mature trees and native grasses. Design work came from Rialto Studio and Stimson Studio, with engineering by Arup and construction by SpawGlass. It opened to the public on December 12, 2020, and a companion elevated footbridge, the Skywalk, opened the following April, rising into the tree canopy along a 1,000-foot span.

The Phil Hardberger Park Conservancy describes it as the nation's first mixed-use wildlife bridge, meaning the first built in the country for both animals and people to use, with a pedestrian trail set off to one side and a low earth berm screening the wildlife side from foot traffic.

Why it was built

Hardberger Park sits on roughly 330 acres that were once the Voelcker family's dairy farm, the last working farm in the area. After the Voelckers’ deaths the property passed into a charitable trust. San Antonio bought it in two bond-funded purchases that then-Mayor Phil Hardberger pushed for: 107 acres in 2006 for $16 million, then the remaining acreage in 2007 for roughly $30 million more, both approved by voters. The trust's proceeds from the sale were donated to local youth and health charities, which is likely where the donation impression comes from. The park opened in two separate pieces: the Blanco Road side in 2010, followed by the Northwest Military side in 2012. The reason for the split launch was Wurzbach Parkway itself. The six-lane road cuts directly through the property, and for the park's first decade there was no way for a person, let alone a deer or bobcat, to move between its two halves without crossing active traffic.

Prior to becoming Hardberger Park, the land was a working dairy farm with pasture, cattle, and farm buildings, though large sections, including its cedar elm woodlands, had never been cleared or developed. The actual ecological work, native habitat restoration, a master plan built around a deliberately “cultivated wild” landscape, and eventually the land bridge itself, all followed the city's purchase, starting with a 2009 groundbreaking and continuing today. Had the sale gone the other way, reporting from the period suggests the land was close to becoming strip centers and apartments instead.

Hardberger had reportedly wanted a connective bridge from early in the park's development, and city and conservancy officials eventually framed the project around habitat connectivity as much as recreation: giving wildlife on both sides access to water, food, and mates without having to risk the parkway.

Cost and funding

The land bridge cost $23 million, split between two funding sources. Voters approved $13 million for the project through a 2017 city bond. The remaining $10 million came from private donations and grants raised by the Hardberger Park Conservancy, the nonprofit that supports the park. Construction ran in phases: site preparation from December 2018 to April 2020, the main structure over Wurzbach Parkway from April to October 2020, and landscaping through December 2020, when the bridge opened.

Is it working?

Nearly six years on, the honest answer is: probably, by the measure the park itself set out to track, though the fuller ecological picture is still being built.

Park staff placed motion-triggered cameras along the bridge (12 of them, as of 2026) specifically to document whether animals were using the full span rather than just wandering onto it. Wendy Leonard, the park's nature preserve officer, said the goal was simple: “linking up habitats so that way wildlife can go from one side of the park to the other.” The footage backs that up. Coyotes and white-tailed deer are confirmed using the bridge in its entirety, and camera traps have also caught a mother bobcat and her nearly grown young crossing, along with sightings of ringtails, opossum, and cottontail rabbits.

The landscape has helped its own case. Native trees and grasses that were barely established in 2020 have filled in substantially, and regular park visitors describe a visibly different, more natural-looking bridge than the bare dirt and small shrubs of its opening month. That hasn't been without setbacks. Freak winter weather in early 2021, a storm cold enough that Texans nicknamed it the “snowpocalypse,” killed a number of the young trees planted on top of the bridge.

It's worth being precise about what the camera evidence does and doesn't prove. Wildlife biologists who study crossings generally distinguish between documenting that animals use a structure and confirming the harder outcomes a crossing is ultimately built for, like measurably reduced vehicle collisions or genetic mixing between previously separated populations. A coyote caught on camera proves the coyote crossed; it doesn't, by itself, prove the bridge is preventing roadkill or keeping either side's wildlife population genetically healthy over the long run. By that stricter standard, the Land Bridge hasn't been running long enough, and hasn't published that kind of population-level data yet. By the more immediate standard the park set for itself, whether animals would actually find and use a purpose-built crossing, the answer so far looks like yes.

Why land bridges matter

Roads are one of the most persistent, invisible forces fragmenting wildlife habitat. In the United States alone, vehicles are involved in more than a million reported collisions with animals every year, and beyond the immediate toll, roads cut populations into smaller, more isolated groups that struggle to find mates, food, and water across a landscape a highway has effectively split in half. Left unaddressed, that isolation can erode genetic diversity over generations, leaving smaller populations more vulnerable to disease and less able to adapt as conditions change.

The evidence that crossings help is substantial. Research reviews put the collision reduction from crossing structures paired with fencing at roughly 80 percent or higher, and some sites report even steeper drops for specific species. Banff National Park's system of 44 overpasses and underpasses along the Trans-Canada Highway has reduced wildlife-vehicle collisions by more than 80 percent overall and over 96 percent for elk and deer specifically, and genetic studies there have confirmed that black bears and grizzly bears are not just crossing but breeding across a highway that once divided them. The Federal Highway Administration frames the goal in exactly those two parts: reducing collisions and restoring the habitat connectivity animals need to move, feed, and reproduce across a landscape that roads have carved up. Increasingly, researchers are also studying a third reason crossings matter: as the climate shifts, the ability to move at all, toward cooler ground, new water sources, or shifting ranges, may matter as much as anything else a crossing provides.

None of that guarantees any individual bridge works as intended. But it's the backdrop against which a project like the Land Bridge gets judged, and why a $23 million overpass over a six-lane parkway is a serious infrastructure investment rather than a park amenity.